Arsenic

Arsenic, symbol As, is a silver-gray, extremely poisonous, semi-metallic element. Arsenic, which is odorless and flavorless, has been known since ancient times, but it wasn’t until the Middle Ages that its poisonous characteristics first become known. Metallic arsenic was first produced in the 17th century by heating arsenic with potash and soap. Arsenic is rarely found in nature in its elemental form and is generally recovered as a by-product of ore processing.

The U.S. Geological Survey reported that no arsenic was removed from domestic ores in the United States. All arsenic metals and compounds used in the U.S. are imported. More than 95 percent of the arsenic consumed is in compound form, mostly as arsenic trioxide, which in turn is converted into arsenic acid. Production of chromated copper arsenate, a wood preservative, accounts for over 90 percent of the domestic consumption of arsenic trioxide. Three companies in the US manufacture chromate copper arsenate. Another company used arsenic acid to produce an arsenical herbicide. Arsenic metal is used to produce nonferrous alloys, primarily for lead-acid batteries.

One area where there is increased consumption of arsenic is in the semiconductor industry. Very high-purity arsenic is used in the production of gallium arsenide. High speed and high frequency integrated circuits that use gallium arsenide have better signal reception and lower power consumption. It is estimated that 30 metric tons per year of high-purity arsenic is used in the production of semiconductor materials.

The largest domestic market for arsenic in the U.S. is in the production of arsenical wood preservatives. That is expected to continue, although there are increasing environmental concerns that could limit its use in the future. Demand for arsenic and arsenic compounds, therefore, derives from new home construction and from renovation and wooden deck construction. Arsenic and arsenic compounds are very toxic and increased scrutiny of products using arsenic is expected to result in more environmental regulations in the future, thus reducing future demand for arsenic.

Recently, small doses of arsenic have been found to put some forms of cancer into remission. It can also help thin blood. Homoeopathists have successfully used undetectable amounts of arsenic to cure stomach cramps. Traditionally used as a nonferrous alloy for enhancing properties such as hardening of lead and resistance to corrosion. Arsenic is also used in the manufacture of glass and in the making of CCA pressure-treated wood.

Supply – US supply of arsenic in 2002 fell to 19,700 metric tons from 25,000 metric tons in 2001. World production of white arsenic (arsenic trioxide) in 2002 was unchanged from 2001 at a 22-year low of 35,000 metric tons. The world’s largest producer by far is China with 46% of world production, followed by Chile with 23% of world production.

Demand – Demand for arsenic fell to 19,600 metric tons in 2002 from 24,900 metric tons in 2001. Of that demand, 17,300 metric tons was for wood preservatives, 700 metric tons for glass, 650 metric tons for non-ferrous alloys and electric usage, and 200 for other uses.

Trade – US imports of trioxide arsenic in 2002 fell to 24,700 metric tons from 31,500 metric tons in 2001. US exports were negligible at 100 metric tons, up from 57 metric tons in 2001.